Medical conditions including: active or chronic infection requiring antimicrobial therapy, serious viral infection (hepatitis, herpes zoster), a single functioning kidney, renal insufficiency (less than one third of normal GFR), significant hepatic dysfunction, pre-existent malignancy, insulin-treated diabetes mellitus, severe benign prostatic hypertrophy, immunosuppression, myelosuppression, lymphopenia, severe pulmonary dysfunction, history of gastrointestinal ulceration active within the last 5 years, history of gastrointestinal bleeding or perforation, or severe cardiac dysfunction.